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Large intestine

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The large intestine is part of the organs of the digestive system. It is the thickest portion of the intestines and is responsible for absorbing water and minerals, in addition to forming feces from food waste and eliminating them from the body.

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What is the large intestine?

The large intestine is a tubular organ of the digestive system . Its function is to absorb the water and minerals of the chyme and form the feces for its elimination . It is made up of: cecum, vermiform appendix, ascending colon, transverse colon, descending colon, rectum and anus.

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  • Definition
  • Characteristics of the large intestine
  • Function
  • Parties
  • Layers
  • Location
  • How does it work
  • Diseases of the large intestine
  • Care
  • How big is
  • What is absorbed in the large intestine
  • How it differs from the small intestine
  • Importance

Definition

It is a tubular organ that forms the last portion of the digestive tract, located between the ileocecal junction and the anal sphincter. It is responsible for preparing digestion wastes for elimination.

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Characteristics of the large intestine

The main characteristics of the large intestine are as follows:

  • The large intestine is the last portion of the digestive tract.
  • It is the widest and shortest portion of the intestine.
  • The large intestine is arranged in three segments : ascending, transverse, and descending.
  • Store stool before disposal.
  • The large intestine contains the intestinal flora , which are colonies of microorganisms that protect us against infections.

Function

  • Absorption: most of the water and ions or electrolytes in the chyme that it receives from the small intestine and compacts the chyme in feces for elimination.
  • Immunity: The bacterial flora of the large intestine protect us from infections.

Parties

The parts of the large intestine are:

  • Blind : It is a blind intestinal pouch that is approximately 7.5 cm long and wide. It is located in the right iliac fossa.
  • Vermiform appendix : it is an intestinal diverticulum of the cecum that measures 6 to 10 cm in length. Its proximal portion is located on the posteromedial aspect of the cecum, below the ileocecal junction. Its distal portion varies in location (retrocecal, subcecal, ileal, perileal, pelvic).
  • Ascending colon  : it is the second portion of the colon, located to the right of the abdominal cavity, from the cecum to the right lobe of the liver.
  • Transverse colon : measures approximately 45 cm in length. It is the largest and most mobile portion of the colon.
  • Descending colon : it is located to the left of the abdominal cavity, from the left colic flexure to the left iliac fossa.
  • Sigmoid colon : It is located between the descending colon and the rectum. It is approximately 45 cm long and is S-shaped. It runs from the left iliac fossa to the third sacral segment.
  • Rectum: it is the portion of the large intestine that is before the anal canal. It is 15 to 20 cm long.
  • Anal canal : It is about 3 to 4 cm long and contains the anal sphincter.

Layers

The layers of the colon are:

  • External muscle: it is uncommon since it does not continue over its entire surface, but rather gathers in the tapeworms of the colon.
  • Serosa: contains numerous epiploic appendages, which are bags of fat.

The anal canal is made up of the following layers:

  • Anal mucosa: contains simple cuboidal epithelium at the valve level; non-keratinized stratified squamous epithelium from the pectinate line to the external anal orifice; and keratinized stratified squamous epithelium in the anus.
  • Anal submucosa: formed by fibroelastic connective tissue.
  • External muscle : contains an internal circular smooth muscle layer and an external longitudinal one.

Location

The large intestine is located in the abdominal cavity, between the ileocecal junction and the anus.

How does it work

The content not used by the small intestine, passes to the large intestine, which through peristaltic movements, absorbs water and minerals. Finally, a waste bolus is formed that will be expelled to the outside through the rectum and anus.

Diseases of the large intestine

  • Irritable bowel syndrome
  • Aganglionic megacolon
  • Hemorrhoids
  • Volvulus
  • Ulcerative colitis
  • Crohn’s disease
  • Constipation
  • Intestinal parasitosis
  • Diverticulitis
  • Diverticulosis
  • Polyps
  • Appendicitis
  • Anal fissure
  • Anal prolapse
  • Cancer

Care

To maintain an adequate intestinal transit, it is important to consume 2 liters of water a day, eat foods rich in fiber and carry out physical activities. In addition to preventing copious food, excessive intake of medications, the consumption of alcoholic beverages and the consumption of tobacco. On the other hand, it is important to control stress levels or strong emotions.

How big is

It measures approximately 1.5 meters in length.

What is absorbed in the large intestine

In the large intestine nutrients are absorbed that were not used by the small intestine, such as water, glucose, electrolytes, vitamin K and B12.

How it differs from the small intestine

  • The large intestine contains colic tapeworms, which are band-shaped condensations of muscle.
  • The haustras are only present in the large intestine; these are saccular formations located between tapeworms.
  • The omental or epliploic appendages are present in the large intestine.
  • The internal diameter of the large intestine is larger than that of the small intestine.
  • The small intestine is much longer than the large intestine.

Importance

The importance of the large intestine is based on the fact that it is the only organ responsible for the formation of feces and eliminating them, in addition to absorbing large amounts of water and nutrients that were not used by the small intestine.

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